1. Field of the Invention
The present invention relates to a terminal having a Real Time Clock (hereafter, RTC) operator and a method of RTC operation using the same. More particularly, the present invention relates to a terminal having an RTC operator, enabling a reduction of power consumption from a backup battery by periodically switching on/off a DC/DC converter, and charging/discharging a capacitor with the power from the backup battery when the power supplied from a main power source is switched off, and a method of RTC operation using the same.
2. Description of the Related Art
Unlike a synchronous Code Division Multiple Access (CDMA) terminal, in an asynchronous mobile communication system, such as a Global System for Communications (GSM) terminal and a General Packet Radio Service (GPRS) terminal, a user must input a time so that an internal clock of the terminal operates correctly.
In the case of a synchronous terminal, the time of an internal clock of the terminal is automatically set during a setting operation using time information received from a network system, and thereby the internal clock always maintains a correct time without requiring a user's input.
However, in the case of an asynchronous terminal, a network system does not send time information to the terminal, and therefore a user of the terminal must input a time. Therefore, each terminal may have a different time setting, and the user may be inconvenienced by having to input the time whenever the terminal is switched on.
In order to solve this problem, the asynchronous terminal uses a backup battery to protect the time information from being erased when the power from a main power source is discontinued. The asynchronous terminal has an internal RTC to manage and display the time information.
However, for the operation of the RTC, the backup battery supplies power to the RTC continuously, which may result in discontinuation of RTC operation when the backup battery is completely discharged. At this moment, the RTC is reset to an initial time setting (generally, “0”), and thereby display of the correct time is not possible.